package com.holly.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.holly.dto.Result;
import com.holly.entity.SeckillVoucher;
import com.holly.entity.VoucherOrder;
import com.holly.mapper.VoucherOrderMapper;
import com.holly.service.ISeckillVoucherService;
import com.holly.service.IVoucherOrderService;
import com.holly.utils.RedisIdWorker;
import com.holly.utils.SimpleRedisLock;
import com.holly.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 服务实现类
 *
 * @author holly
 * @since 2022-05-08
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    private class VoucherOrderHandler implements Runnable {
        private String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有异常消息，结束循环
                        break;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        // 创建锁对象
        RLock redisLock = redissonClient.getLock("lock:order:" + userId);
        // 尝试获取锁
        boolean isLock = redisLock.tryLock();
        // 判断
        if (!isLock) {
            // 获取锁失败，直接返回失败或者重试
            log.error("不允许重复下单！");
            return;
        }

        try {
            // 5.1.查询订单
            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
            // 5.2.判断是否存在
            if (count > 0) {
                // 用户已经购买过了
                log.error("不允许重复下单！");
                return;
            }

            // 6.扣减库存
            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1") // set stock = stock - 1
                    .eq("voucher_id", voucherId).gt("stock", 0) // where id = ? and stock > 0
                    .update();
            if (!success) {
                // 扣减失败
                log.error("库存不足！");
                return;
            }

            // 7.创建订单
            save(voucherOrder);
        } finally {
            // 释放锁
            redisLock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        long orderId = redisIdWorker.nextId("order");
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );
        int r = result.intValue();
        // 2.判断结果是否为0
        if (r != 0) {
            // 2.1.不为0 ，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        // 3.返回订单id
        return Result.ok(orderId);
    }

    /*private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
            while (true){
                try {
                    // 1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    // 2.创建订单
                    createVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }*/


//    @Transactional
//    public void createVoucherOrder(VoucherOrder voucherOrder) {
//        //一人一单问题
//        Long userId = voucherOrder.getUserId();
//        //查询订单
//        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
//        //判断是否存在该订单
//        if (count > 0) {
//            log.error("该用户已经购买过一次");
//            return;
//            //return Result.fail("该用户已经购买过一次");
//        }
//
//        //扣减库存
//        boolean success = seckillVoucherService.update()
//                .setSql("stock = stock - 1")
//                .eq("voucher_id", voucherOrder.getVoucherId())
//                .gt("stock", 0)//锁库存
//                .update();
//        if (!success) {
//            log.error("库存不足");
//            //return Result.fail("库存不足");
//        }
//
//        //创建订单
////        VoucherOrder voucherOrder = new VoucherOrder();
////        long orderId = redisIdWorker.nextId("order");
////        voucherOrder.setId(orderId);
////        voucherOrder.setUserId(UserHolder.getUser().getId());
////        voucherOrder.setVoucherId(voucherId);
//        save(voucherOrder);
//    }
//
//    private IVoucherOrderService proxy = null;
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        Long userId = UserHolder.getUser().getId();
//        //执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(),userId.toString());
//        //判断结果是否为0
//        int r = result.intValue();
//        if (r != 0) {
//            //不为0，代表没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        //为0，有购买资格
//        VoucherOrder voucherOrder = new VoucherOrder();
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        voucherOrder.setVoucherId(voucherId);
//        voucherOrder.setUserId(userId);
//        //把下单信息保存到阻塞队列中
//        orderTasks.add(voucherOrder);
//
//        //获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//
//        //返回订单id
//        return Result.ok(orderId);
//    }



//    private void handleVoucherOrder(VoucherOrder voucherOrder) {
//        Long userId = voucherOrder.getUserId();
//        Long voucherId = voucherOrder.getVoucherId();
//        //创建锁对象
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁
//        boolean isLock = lock.tryLock();
//        //判断是否获取锁成功
//        if (!isLock) {
//            //获取锁失败，返回失败或者重试
//            log.error("不允许重复下单");
//            return;
//        }
//        try {
//            proxy.createVoucherOrder(voucherOrder);
//        } finally {
//            //释放锁
//            lock.unlock();
//        }
//    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始");
//        }
//        //判断秒杀是否结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束");
//        }
//        //判断库存
//        if (voucher.getStock() < 1) {
//            return Result.fail("库存不足");
//        }
//
//        Long userId = UserHolder.getUser().getId();
//        //创建锁对象
//        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁
//        boolean isLock = lock.tryLock();
//        if (!isLock) {
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            //获取代理对象(事务）
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            //返回订单id
//            return proxy.createVoucherOrder(voucherId);
//        } finally {
//            //释放锁
//           lock.unlock();
//        }
//
//    }

}
